Slide Rule

A slide rule is a mechanical device used for mathematical calculations, particularly multiplication and division, before electronic calculators became common. It consists of a fixed outer scale and a sliding inner scale, both marked with numbers. By aligning these scales according to the operation, users can perform rapid approximations of complex calculations like roots, logarithms, and exponentials. The slide rule relies on logarithmic scales to facilitate these functions, making it a valuable tool for engineers and scientists in the 19th and early 20th centuries. It is portable, durable, and provides a visual understanding of mathematical relationships.